Renal 1 Flashcards
Renal tubular defects - types
- Fanconi syndrome
- Bartter syndrome
- Gitelman syndrome
- Liddle syndrome
- Syndrome of apparent minelocorticoid excess
Fanconi syndrome - pathophysiology / results in
Generalized reabsorptive defect in early proximal convoluted tubule –> increased amino acids, glucose, HCO3- and PO4- – Metabolic acidosis (proximal renal tubular acidosis)
causes of Fanconi syndrome
- hereditary defects (Wilson disease, tyrosinemia, glycogen storage disease, cystinosis)
- iscemia
- multiple myeloma
- nephrotoxins/drugs (expired tetracyclines, ifosfamide, cisplatin, tenofovir, lead poisoning)
Bartter syndrome - pathophysiology (and result in)
Reabsorptive defect in thick ascending loop oh Henle
–> affects Na+/K+/2CL- cotransporter –>
1. hypokalemia
2. metabolic alkalosis
3. hypercalciuria
LIKE LOOP DIURETICS
Gitelman syndrome - pathophysiology (results in)
Reabsosptive defect in Distal convoluted tubule LIKE THIAZIDE 1. hypokalemia 2. hypomagnesia 3. metabolic alkalosis 4. hypocalciuria
Gitelman syndrome vs Barrter syndrome according to severity
Barrter is more severe
Liddle syndrome - pathophysiology
Gain of function mutation –> increased Na+ reabsorption in collecting tubules (high activity of epithelial channel)
situation that mimics Liddle syndrome
hyperaldosternism (but aldosterone is nearly undetectable)
Liddle syndrome –> ….. (result in)
- hypertension
- hypokalemia
- metabolic alkalosis
- low aldosterone
Liddle syndrome - mode of inheritance / treatment
AD
amiloride
Syndrome of Apparent Mineralocorticoid excess - pathophysiology
hereditary deficiency of 11β-hydroxysteroid dehydrogenase which normally converts cortisol (can activate mineralocorticoid receptors) to cortizone (inactivate on mineralocorticoid receptors) in cell containing mineralocorticoid receptors –> increased mineralocorticoid activity
Syndrome of Apparent Mineralocorticoid excess - manifestations
- hypertension
- hypokalemia
- metabolic alkalosis
- low serum aldosterone levels
P02, PCO2, HCO3-, ph - normal ranges
PO2: 75-105 mm Hg
PCO2: 33-44 mm Hg
HCO3-: 22-28 mEq/L
pH: 7.35-7.45
Winters formula?? is a formula used to evaluate
respiratory compensation in a metabolic acidosis
PCO2=1.5 (HCO3-) + 8 +/- 2
Winters formula - explanation
If measured PCO2 is bigger than predicted PCO2 –> concominant respiratory acidosis
If measured PCO2 is smaller than predicted –> concomitant respiratory alkalosis
Metabolic alkalosis - DDx
- loop diuretics
- vomiting
- antiacids
- hyperaldosteronism
- thiazide use
- Hypokalemia
- several renal tubular defects
Respiratory alkalosis - DDx
Hyperventilation:
- Hysteria
- Hypoxemia (eg. high altitude)
- Pulmoary embolism
- Tumor
- salicylates (early)
Respiratory acidosis - DDx
Hypoventilation:
- Airway obstruction
- Acute lung disease
- Chronic lung disease
- Opioids/sedatives
- weakening of respiratory muscles
Metabolic acidosis - next step
Check anion gap = Na+ - (CL+HCO3-):
more than 12 –> anion gap metabolic acidosis
8-12 –> normal anion gap metabolic acidosis
anion gap metabolic acidosis - DDx
- Methanol (formic acid)
- Uremia
- Diabetic ketoacidosis
- Propylene glycol
- Iron tablets
- ISONIAZIDE
- Lactic acidosis
- Ethylene glycol (–> oxalic acid)
- Salicilates (late)
normal anion gap metabolic acidosis - DDx
- Hyperalimentation (artificial supply of nutrients, typically intravenously)
- Addison disease
- Renal tubular acidosis
- Diarrhea
- Acetazolamide
- Spironolactone
- saline infusion
Renal tubular acidosis - types
- Distal tubular acidosis (type 1)
- Proximal renal tubular acidosis (type 2)
- Combined proximal and distal renal tubular acidosis (type 3)
- Hyperkalemic renal tubular acidosis (type 4)
Metabolic acidosis - predicted compensatory response
1 meq/L decrease in HCO3- –> 1.3 mmHg decrease in PCO2
Metabolic alkalosis - predicted compensatory response
1 meq/L increase in HCO3- –> 0.7 mmHg increase in PCO2
Respiratory acidosis - predicted compensatory response
acute: 1 mmHg increase in PCO2 –> 0.1 meg/L increase in HCO3-
chronic: 1 mmHg increase in PCO2 –> 0.4 meq/L increase in HCO3-
Respiratory alkalosis - predicted compensatory response
acute: 1 mmHg decrease in PCO2 –> 0.2 meq/L decrease in HCO3-
chronic: 1mmHg decrease in PCO2 –> 0.4 meg/L decrease in HCO3-
Renal cell carcinoma - risk factors
- Smoking
- obesity
- gene deletion of chromosome 3 (sporadic or inheritance as von Hippel-Lindau
Renal cell carcinoma - paraneoplastic syndromes
- EPO
- ACTH
- PTHrP
- RENIN
Renal cell carcinoma - prognosis? (why)
poor:
- Resistant to chemotherapy and radiation therapy
- Silent cancer –> comonly presents as a metastatic neoplasm
Renal oncocytoma - clinical manifestations
- painless hematuria
- flank pain
- abdominal mass
Renal oncocytoma - treatment
often resected to exclude malignancy
Squamous cell carcinoma of the bladder - clinical manifestation
painless hematuria
Squamous cell carcinoma of the bladder - risk factors
- Schistosoma haematobium infection (Middle East)
- Chrinic cystitis
- smoking
- chronic nephrolithiasis
Transition cell carcinoma - manifestations
painless hematuria
Calcium oxalate stones are precipitated by (beside low ph)
- ethylene glycol (antifreeze) ingestion
- vitamin C abuse
- malabsorption (Crohn disease)
- hypocitraturia –> low ph
kidney calcium stone treatment
calcium oxalate –> thiazides, citrate, low-sodium diet
calcium phosphate –> thiazides
Ammonium magnesium phosphate stone (sturvite) are caused by
infection with urease + bugs (eg. Proteus mirabilis, Staphylococcus saprophyticus, Klebsiella) that hydrolize urea to ammonia –> urina alkalization
Ammonium magnesium phosphate stones (sturvite) - treatment
- eradication of underling infection
2. surgical removal of stone
Uric acid stones - risk factors
- low sodium diet
- alkalinization of urine
- chelating agents if refractory
kidney stones - types and urine crystals
- Calcium oxalate –> shaped like envelope or dumbbell
- Caclicum phosphate –> wedge-shaped prism
- Ammonium magnesium phosphate –> coffin lid
- Uric acid –> Rhomboid or rosettes
- Cystine –> hexagonal
Urinary incontinence - types
- Stress incontinence
- Urgency incontinence
- Mixed incontinence
- Overflow incontinence
urinary Stress incontinence - mechanism
Outlet incompetence (urethral hypermodility or intrinsic sphincteric deficiency –> leak with high intra-abdominal pressure (eg. sneezing, lifting)
urinary Stress incontinence - increased risk with
obesity
vaginal delivery
prostate surgery
urinary Stress incontinence - management
kegel exercise, weight loss. pessaries
urinary Urgency incontinence - mechanism
Overactive bladder (detrusor instability) –> leak with urge to void immediately
urinary Urgency incontinence - treatment
- pelvic floor muscle strengthening (Kegel) exercise
- bladder training (timed voiding, distraction and relaxation techniques)
- antimuscarinics (oxybutynin)
Overflow incontinence - mechanism
incomplete emptying (detrusor underactivity - weak to emoty the bladder or outlet obstruction) –> leak with overfilling –> increased postvoid residual (urinary retention) on cathetirization or ultrasound
Overflow incontinence - treatment
catherterization relieve obstruction (α-blockers for BPH)
3 MCC of UTI (in order)
- E. Coli
- S. saprophyticus
- Klebsiella pneumoniae
UTI - diagnostic markers
- leukocyte esterase –> WBC activity
- Nitrate test –> reduction of urinary nitrates by bacterial species (indicates gram (-) organism, esp E. coli)
- Urease test –> urease-producing bags (eg. Proteus, klebsiella)
acute renal failure (Acute kidney injury) - TYPES
- Prerenal azotemia
- Intrinsic renal failure
- postrenal azotemia
Prerenal azotemia - urine osmolairty (mOsm/Kg), urine Na+ meq/L, FENa, Serum BUN/Cr
- urine osmolairty –> more than 500
- urine Na+ less than 20
- FENa less than 1%
- Serum BUN/Cr >20
Intrinsic renal failure - due to
- acute tubular necrosis or ischemia/toxins
- less commonly due to acute glomerulonephritis (RPGN, hemolytic uremic syndrome) or acute interstitial nephritis
intrinsic failure - urine osmolairty (mOsm/Kg), urine Na+ meq/L, FENa, Serum BUN/Cr
- urine osmolairty –> less than 350
- urine Na+ more than 40
- FENa more than 2%
- Serum BUN/Cr less than 15
postrenal azotemia - urine osmolairty (mOsm/Kg), urine Na+ meq/L, FENa, Serum BUN/Cr
- urine osmolairty –> less than 350
- urine Na+ more than 40
- FENa more than 1% (mild) or 2% (severe)
- Serum BUN/Cr varies
Acute interstitial renal nephritis (tubulointesritital nephritis) - clinical presentation/findings
IT CAN BE ASYMPTOMATIC 1. Fever 2. rash 3. hematuria (casts) 4. costovertebral angle tenderness 5. pyuria (classically eosinophils) 6. azotemia 7. oliguria (days to weeks after the factor) RESULTS IN ACUTE RENAL FAILURE
causes of Acute interstitial renal nephritis (tubulointesritital nephritis)
- drugs that act as haptens, inducing hypersensitivity (eg. diuretics, penicillin derivatives, PPIs, sulfonamides, rifampin, NSAID)
- Systemic infections (eg. mycoplasma)
- Autoimmune diseases (eg. Sjogren syndrome, SLE, sarcoidosis)
Acute interstitial renal nephritis (tubulointesritital nephritis) may progress to
renal papillary necrosis
renal papillary necrosis - symptoms/findings
- gross hematuria
- proteinuria
- flank pain
causes of renal papillary necrosis
- Sickle cell disease or trait
- acute pyelonephritis
- NSAID (or phenacetin)
- DM
- Acute interstitial renal nephritis
May be triggered by recent infection or immune stimulus
MCC of acute kidney injury in hospitalized patients
Acute tubular necrosis
Acute tubular necrosis - prognosis
can be fatal, esp during initial oligurinc phase
Acute tubular necrosis - FENa
more than 2%
Acute tubular necrosis - key finding
granular (muddy brown) casts
Acute tubular necrosis - stages
- inciting event
- Maintenance phase - oliguric
- Recovery phase - polyuric
Acute tubular necrosis - maintenance phase - risk for
- hyperkalemia
- metabolic acidosis
- uremia
Acute tubular necrosis - Recovery phase - findings
BUN and creatinine fall
Acute tubular necrosis - recovery phase - risk for
hypokalemia
Acute tubular necrosis can be caused by …. (groups)
- ischemic factors
2. nephrotoxic factors
Acute tubular necrosis - nephrotoxic factors - mechanism
2ry to injury resulting from toxic substance (eg. aminglycosides, radiocontrasts agents, lead, cisplatin), crush injury (myoglobinuria), hemoglobinuria
Cast in urine - types
- RBC casts
- WBC casts
- Fatty casts (oval fat bodies)
- Granular (“muddy brown”) casts
- Waxy casts
- Hyaline casts
RBC casts - seen in
- glomerulonephritis
2. malignant hypertension
WBC cast - seen in
- tubulointerstitial inflammation
- acute pyelonephritis
- trasnplant rejection
Fatty casts (oval fat bodies) - seen in / associated with
Nephrotic syndrome
- Maltese-cross sign under polarized light
Granular (“muddy brown”) vs waxy casts - seen in / cells
granular –> acute tubular necrosis
waxy –> renal failure
BOTH ACELLULAR
Hyaline casts - seen in / contain
nonspecific, can be normal finding, often in concentrated urine samples
- protein (acellula)
Nomenclature of glomerular disorders - focal (characteristcs and example)
- less than 50% of glumeri are involved
- ex. focal segmental glomerulosclerosis
Nomenclature of glomerular disorders - diffuse (characteristcs and example)
- more than 50% of glumeri are involved
- ex. diffuse proliferative glumerulonephritis
Nephritic syndrome vs nephrotic syndrome according to mechanism
Nephritic syndrome –> GBM disruption
Nephrotic syndrome –> podocyte disruption –> barier impaired
Nephritic syndrome - symptoms and findings
- Hypertension (salt secretion and periorbital edema)
- increased BUN and creatinine
- oliguria
- hematuria (with RBCs in urine)
- Proteinuria in Subnehrotic range (in severe cases may be in nephrotic range)
Nephritic syndrome - diseases?
- acute poststreptococcal glomerulonephritis
- Rapidly progressive glomerulonephritis
- IgA nephropathy (Berger disease)
- Alport syndrome
- Membranoproliferative glomerulonephritis
- Diffuse proliferative glomerulonephritis
Nephrotic syndrome - symptoms and findings
- Massive proteinuria (>3.5g/day) with hypoalbuminemia (pitting edema in soft tissues)
- hyperlipidemia (frothy urine with fatty casts)
- edema
- hypogammaglobulinemia (increased risk of infection)
- loss of antithrombin III –> hypercoagulable state
Nephrotic syndrome - diseases (and if 1ry or 2ry)
- focal segmental glomeulosclerosis (1ry or 2ry)
- minimal change disease (lipoid nephrosis) (1ry or 2ry)
- Membranous nephropathy (membranous glomerulonephritis) (1ry or 2ry)
- Amyloidosis (2ry)
- Diabetic glomerulonephropathy
Nephritic-nephrotic syndrome?
severe nephritic syndrome with profound GBM damage that may damages the glomerular filtration charge barrier (if damage to GBM is severe enougj to damage charger barrier)
–> nephrotic-range proteinuria (>3.5g.day) and concominant features of nephrotic syndrome
Causes of Nephritic-nephrotic syndrome
can occur with any form of nephritic syndrome, but is most common seen with
- diffuse proliferative glomerulonephritis
- Membranoproliferative glomerulonephritis
Nephritic vs nephrotic vs Nephritic-nephrotic syndrome according to protein excreted per day
nephritic: Proteinuria in Subnehrotic range (less than in severe casees may be in nephrotic range
nephrotic: Massive proteinuria (>3.5g/day) with hypoalbuminemia
Nephritic-nephrotic syndrome: nephrotic-range proteinuria (>3.5g.day)
Acute poststreptococcal glomerulonephritis - age / when
Most frequently seen in children (may also occur in adults)
- 2-4 weeks after A streptococcal infection of of skin (impetigo) or pharynx
Acute poststreptococcal glomerulonephritis - treatment
resolves spontaneously
Acute poststreptococcal glomerulonephritis - lab
- strep titers/serologies
- low complement levels due to consumption
- LM: glomeruli enlarged and hypecellular
- IF: (starry sky) granular appearance (lumpy-bumpy) due to IgG, IgM and C3 deposotio along GBM and mesangium
- EM: subepithelial immune complex (IC) humbs
causes of Rapidly progressive (crescentic) glomerulonephritis
several diseases processes may result in this pattern
- Goodpasture - anti-GBM + anti alveolar BM
- Granulomatosis with polyangiitis (Wegener) - PR3-ANCA/c-ANCA
- Microscopic polyangitis, Churg strauus - MPO-ANCA/p-ANCA
- poststreptococcal glomerulonephritis
- Diffuse proliferative glomerulonephritis
Rapidly progressive (crescentic) glomerulonephritis - image
LM: crescent moon shape –> consist of fibrin and plasma proetins (eg. C3b) with glomerular parietal cells, monocytes, macrophages
IF: a. Goodpasture –> linear b. wegener, Microscopic polyangitis –> negative IF (Pauci-immune –> no IG/C3 deposotion) c. if PSGN or Diffuse proliferative glomerulonephritis –> granular
Rapidly progressive (crescentic) glomerulonephritis - treatment / prognosis
emergent plasmapheresis
poor prognosis
Diffuse proliferative glomerulonephritis - mechanism
due to SLE or membranoproliferative glomerulonephritis
Diffuse proliferative glomerulonephritis - image
LM - wire looping of capillaries
EM: subendothelial and sometimes intramembranous IgG-based ICs often with C3 deposotion
IF: granular
IgA nephrpathy (Berger disasee) -mechanism/presentation
episodic gross hematuria that occurs concurrently with respiratory or GI tract infection (IgA is secreted by mucosal linings) –> IgA complex
RENAL PATHOLOGY OF HENOCH-SCHONLEIN PURPURA
IgA nephrpathy (Berger disasee) - image
LM - mesangial proliferation
EM - mesangial IC depositis
IF - IgA-based IC deposits in mesangium
Alport syndrome - mechanism / mode of inheritance
Mutation in type IV collagen –> thinning and splitting of glomerular basement membrane
MC X-linked dominant
Alport syndrome - manifestation
- Eye problem (eg. retinopathy, lens dislocation)
- glomerulonephritis –> isolated hematuria
- sensorineural deafness
Alport syndrome - image
Basket-weave” appearance on EM
Mebranoproliferative glomerulonephritis (MPGN) - mechanism
type 1 --> 2ry to hepatitis B or C infection, May also be idiopathic type 2 (dense deposit disease) --> associated with C3 nephritic factor (autoantibody that stabilize C3 convertase) --> low serum C3 levels
Mebranoproliferative glomerulonephritis (MPGN) - prognosis
poor response to steroids –> progress to chronic renal failure
Mebranoproliferative glomerulonephritis (MPGN) type I - image
subendothelial immune complex (IC) deposits with granular IF
tram track appearance on PAS stain and H&E stain due to GBM splitting caused by mesangial ingrowth
Mebranoproliferative glomerulonephritis (MPGN) type I vs type to according to location of deposits
type 1 –> subendothelial
type 2 –> intramembranous
MCC of nephrotic syndrome in children / treatment
Minimal change disease (lipoid nephrosis)
- excellent response to corticosteroids
Minimal change disease (lipoid necrosis) - image
LM - normal glomeruli, lipid may be seen in PCT cells
IF - normal
EM - effacement of foot process
MCC of nephrotic syndrome in African and Hispanics
Focal segmental glomerulosclerosis
causes of focal segmental glomerulosclerosis
- Can be 1ry (idiopathic)
- 2ry to other conditions –> a. HIV infection b. Sickle cell anemia c. heroin abuse d. massive obesity
e. interferon treatment f. chronic kidney disease due to congenital malformations
focal segmental glomerulosclerosis - course and treatment
may progress to chronic renal disease
1ry disease has incosistent response to steroids
focal segmental glomerulosclerosis - image
LM - segmental sclerosis and hyalinosis
IF - often (-), but may be + for nonspecific focal deposits of IgM, C3, C1…
EF - effacement of ffot process similar to minimal
MC cause of 1ry nephrotic syndrome in Caucasian adults
Membranous nephropathy (membranous glomerulonephritis)
causes of Membranous nephropathy (membranous glomerulonephritis)
- primary (antibodies to phospholypase A2 receptor)
2. 2ry to: a. drugs (eg. NSAIDs, penicillamine) b. infections (HBV, HCV) c. SLE d. solid tumors
causes of Membranous nephropathy (membranous glomerulonephritis) - course and treatment
may progress to chronic renal disease
1ry disease has poor response to steroids
Membranous nephropathy (membranous glomerulonephritis) - image
LM - diffuse capillary and BM thickenning
IF - granular (immune complex)
EM - “spike and done” appearance with subepithelial deposits
nephrotic syndrome - amyloidosis - image
LM - congo red stain shows apple green birefringence under polairzed light due to amyloid deposition in the mesangium
MCC of end-stage renal disease in US
Diabetic glomerulonephropathy
Diabetic glomerulonephropathy - mechanism
Nonenzymatic glycosylation of GBM –> increased permeability, thickening
Nonenzymatic glycosylation of efferent arterioles –> increased GFR –> mesangial expansion
HCV, HBV nephritis - types
nephrotic –> Membraous nephropathy (membranous glomerulonephritis)
nephritic –> membranoproliferative glomerulonephritis
Lupus nephritis - types
nephritic - diffuse proliferative glomerulonephritis
nephrotic - membranous glomerulonephritis
MC nephropathy worldwide
IgA nephropathy (Berger disease)
glomerular disease with subepithelial deposits
- Acute poststreptococcal glomerulonephritis
2. Membranous nephropathy (membranous glomerulonephritis)